Thyme

Active compounds: Thyme contains volatile oils (mainly thymol and carvacrol) plus phenolic compounds that have antimicrobial, antiviral (in vitro), anti-inflammatory, antispasmodic and expectorant effects — properties that can reduce cough, loosen mucus and calm inflamed airways. Wiley Online Library ScienceDirect

Symptom effect (cough/expectoration): Thyme preparations have documented expectorant and antitussive activity in humans (often when used as standardized extracts or in combination products), which explains why people with bronchitic cough or productive cough often improve. European Medicines Agency (EMA) archive.ansm.sante.fr

Supporting regulatory assessment: The European Medicines Agency (HMPC) has a full herbal monograph for thyme that recognises traditional medicinal uses for respiratory tract conditions and reviews its pharmacology and quality/standardisation issues (essential-oil content, chemotypes). European Medicines Agency (EMA)

Important: the strongest clinical support is for standardized thyme extracts and licensed herbal medicines (e.g., combination products such as thyme + ivy or thyme + primula) — not for arbitrary essential-oil ingestion. Always follow product labels and check with a clinician for people who are pregnant, breastfeeding, on blood thinners, or have serious illness.

A. Licensed herbal preparations (best evidence / preferred when available)

• Bronchipret® syrup / drops (thyme + ivy; BNO 1200) — used in clinical studies and marketed OTC. Typical dosing from the manufacturer / leaflet:
• Syrup (adults & adolescents ≥12 y): 5.4 mL, three times daily (children have age-adjusted doses). Use the measuring cup; shake before use. If no improvement in ~10 days or if breathing worsens, see a doctor. Package leaflet and product monograph list exact age bands and precautions. Thiemebronchipret.de
• Other thyme combination tablets/syrups (thyme + primrose root etc.) have also been used in RCTs — those product leaflets specify tablet or syrup doses (e.g., one tablet three times daily or similar). Follow the specific product leaflet. Thieme ICA Health

B. Standard home/herbal use (tea, tincture)

• Thyme tea (infusion) — commonly prepared and used as a soothing respiratory infusion. Traditional dosage guidance (monographs) suggests: 1–2 g dried thyme (or a small handful fresh) per cup, 3–4 times daily as an oral infusion. (Different national monographs give similar ranges.) edaegypt.gov.eg webprod.hc-sc.gc.ca
• Tinctures / liquid extracts — herbal pharmacopoeia and national monographs describe extract ratios and typical concentrations (e.g., certain fluid extracts correspond to ~30–50 mg crude herb per mL in finished product). If using a commercial tincture, follow the manufacturer label or monograph guidance; homemade tinctures vary widely and are not standardized. webprod.hc-sc.gc.ca European Medicines Agency (EMA)

C. Essential oil / inhalation

• Inhalation of diluted thyme oil for steam inhalation is sometimes used for symptomatic relief, but do NOT ingest undiluted essential oil. If inhaling, keep the oil very dilute and avoid direct application to mucous membranes or giving to young children. Essential oils vary by chemotype and concentration (see EMA monograph). European Medicines Agency (EMA) Nature

Human clinical evidence (high-relevance items):

• Randomized, double-blind clinical trial (thyme + ivy fluid extract): a multicentre, double-blind, placebo-controlled trial (N≈361) showed the thyme/ivy combination reduced cough frequency and improved bronchitis symptoms vs placebo (11-day treatment, product used in study = Bronchipret® Saft in the trial). This is one of the main RCTs supporting thyme-containing products for acute bronchitic cough. Thieme Europe PMC
• Observational / pharmacy-based real-world studies of thyme/ivy formulations (BNO 1200) report rapid reduction in cough severity and good tolerability in large practice-based cohorts. These are supportive, though non-randomized. Taylor & Francis Online Startseite
• Systematic reviews and reviews of medicinal plants for upper respiratory infections note thyme (often in combination with other herbs such as ivy or primula) as one of the herbal products with clinical studies supporting symptomatic improvement in cough/bronchitis. However, many trials study combinations or commercial extracts rather than raw kitchen thyme. MDPI ScienceDirect

Mechanistic / lab work (supports plausibility)

• In vitro and animal studies show thymol/carvacrol inhibit various bacteria and some viruses in lab tests and have anti-inflammatory and mucolytic effects — these pharmacologic actions help explain the observed clinical cough/expectorant benefits. But in-vitro antiviral activity doesn’t automatically translate to proven antiviral effect in people. Wiley Online Library ScienceDirect

Summary: there is clinical evidence — strongest for standardized thyme extracts and marketed combination products (thyme + ivy/primrose) to relieve cough and help expectoration in acute bronchitis or productive cough. Single-herb, non-standardized uses (e.g., home tea) are plausible and commonly used, but carry less consistent trial data. Thieme MDPI